(Noun) A male who persistently or illegitimately keeps the company, or attempts to gain the attention of an attractive or potentially desired female, even though he has no chance of forming a relationship or true friendship with her, often to the annoyance of other males. The girl may or may not be aware that the guy is pussykeeping her.
The word has been in use at Darwin bar, Cambridge for several years. Not the same meaning as cockblocker.

"I really fancy that girl, but that guy she is with is such a pussykeeper!" Or, "He's not her boyfriend, he's just a pussykeeper."